1. Field
Aspects of embodiments of the present invention are directed toward efficient ways of creating process window enhanced photomask layouts.
2. Description of Related Art
Photolithography is used, for example, to fabricate semiconductor devices, such as microprocessors, with a high density of circuits. When the size of a circuit is reduced by half in both length and width, the corresponding number of circuits that can fit in the same area grows by a factor of four, thus allowing a greater number of devices or more complex devices to fit in the same amount of space. Accordingly, improving the photolithography process to produce smaller circuits is an ongoing effort.
Photolithography makes use of photomasks to pattern two-dimensional features on, for example, a wafer (such as a silicon wafer) used to fabricate semiconductor devices. Photolithography uses light to expose the features through the photomask and onto a light sensitive material (such as photoresist). Present photolithography uses ultraviolet light, such as 193 nanometer (nm) wavelength, to produce feature sizes down to around 50 nm. However, when pushing the limits (such as diffraction limits) of the optical wavelength, the resulting features may no longer resemble the pattern in the photomask.